Basic Symptoms and Syndromes in Diseases of Cardiovascular System.

Concrete aims:

• to combine the results of questioning, physical and instrumental examination of a patient with specific pathology of cardiovascular system and differentiate the basic symptoms and syndromes of their damage

• to identify the basic syndromes in diseases of cardiovascular system and explain the mechanisms of their development

• to choose the adequate methods of examination in specific diseases of cardiovascular system

• to demonstrate the possessing of modern classifications of the diseases of cardiovascular system

Topic 1. The Main Syndromes of Heart Failure

Class lasts: 3 hours

Chronological class structure:

Control of initial standard of knowledges- 20 min.

Teacher′s demonstration of practical skills - 60 min.

Sudents′ independent work: - 30 min.

Control of ultimate standard of knowledges- 15 min.

Sum up of the class, homework- 10 min.

Questions for theoretical preparation: Heart failure. Etiology and pathophysiology of heart failure. Modern classification of heart failure (New York Heart Association functional class, stage of heart failure, haemodynamic forms of heart failure). Clinical manifestations of heart failure. Instrumental methods of examination. Acute vascular insufficiency (syncope, collapse, shock). Syncope.

Syndrome of cardiovascular failure

Heart failure is a pathological condition which characterized by decreased contractility of the myocardium, reduction of cardiac output in which the cardiovascular system fails to supply the necessary amount of blood to the organs and tissues for their adequate function.

This condition arises due to the affection of the heart or of the vessels, or it may be combined disorders of the cardiovascular system.

The syndrome of cardiovascular failure is divided into 2 groups:

• heart failure: acute (acute left ventricular heart failure, acute left atrial heart failure, acute right ventricular heart failure) and chronic (chronic left ventricular heart failure, chronic left atrial heart failure, chronic right ventricular heart failure and total chronic heart failure);

• vascular failure: syncope, collapse and shock.

Etiology

Heart failure may develop in case of overloading or overstrain of the myocardium by "pressure" (hypertension, aortic stenosis, stenosis of the pulmonary orifice), by "volume" (mitral or aortic regurgitation), and also owing to diseases affect primarily the myocardium and its metabolism. Affection of the myocardium may be due to infectious, inflammatory and toxic damage of the myocardium (myocarditis, cardiomyopathy, intoxication of the myocardium by alcohol, narcotic drugs, and other poisons), insufficient blood supply to the myocardium (disordered coronary circulation, anemia), metabolic disorders, and endocrine dysfunction.

Common causes of heart failure:

• ischemic (coronary) heart disease;

• arterial hypertension;

• dilated cardiomyopathy;

• heart valve diseases;

• hypertrophic cardiomyopathy;

• restrictive cardiomyopathy;

• constrictive pericarditis;

• high-output heart failure;

• chronic anemia;

• atrioventricular shunts;

• thyrotoxicosis.

Pathogenesis. The clinical syndrome related to organ hypoperfusion and inadequate tissue oxygen delivery due to a low cardiac output and decreased cardiac reserve, as well as pulmonary and systemic venous congestion. Heart failure is associated with complex neurohormonal changes including activation of the renin-angiotensin-aldosterone and the sympathetic nervous systems. At first these changes may help to compensate cardiac function by altering the afterload or preload and by increasing myocardial contractility. Ultimately they become counterproductive and reduce cardiac output by causing an inappropriate and excessive increase in peripheral vascular resistance. A vicious cycle may be established because a fall in cardiac output will cause further neurohormonal activation and increasing peripheral vascular resistance. The onset of peripheral edema is due to salt and water retention caused by impaired renal perfusion and secondary aldosteronism.

Heart failure may develop as a result of impaired myocardial contraction due to decreasing of number functional activity of cardiomyocites - systolic dysfunction. Which may observe in patients with inflammation of myocardium, cardiosclerosis, hypertension, non-compensated regurgitation and dilated cardiomyopathy.

Heart failure may arise due to poor ventricular filling caused by disorder of active relaxation and increasing of rigidity of myocardium due to hypertrophy, fibrosis and infiltration - diastolic dysfunction, which may observe in patients with constrictive pericardities, hypertrophic cardiomyopathy.

Systolic and diastolic dysfunctions often coexist, particularly in patients with hypertension, ischemic (coronary) heart disease.

Compensatory mechanisms in heart failure: tachycardia, Frank-Starling's mechanism, myocardial hypertrophy, tonogenic dilation and slow blood flow.